An elderly couple died after their car collided with two separate vehicles on the Desert Road yesterday afternoon.
Malcolm John Anderson, 82, and his passenger and wife Margaret Catherine Anderson, 76, were killed in the crash about 1.30pm about 27km south of Turangi, in the Three Sisters area.
They were travelling north and collided with a southbound BMW convertible.
After the initial collision their Suzuki was struck by a southbound Nissan van, coming to rest amidst tussock on the eastern side of the road.
Police are investigating what caused the first collision.
Senior Constable Dave Frazer, a crash analyst with the Taupo police, said it appeared the Suzuki may have crossed the centre line.
"But why, we're not sure yet. Whether the driver may have had a medical condition, or whether there's been something else involved ... we're still trying to piece it all together."
The weather at the time of the crash was fine, and the road was dry. Speed was not a factor.
Mr Frazer said the Suzuki crumpled on the left side where the van struck it, and believed the impact was too much for the couple, given their age.
The driver of the BMW, a 48-year-old man from Wanaka, received minor injuries.
He was treated at Taupo Hospital and discharged last night.
Two French tourists travelling with him were uninjured and continued their journey south with another motorist.
A 28-year-old man from Rongotea who was driving the van was taken to Palmerston North Hospital with moderate injuries.
Fire and ambulance crews attended the crash and State Highway 1 was closed for four and a half hours while the scene was marked up.
Last month, police hailed the road toll this year as "truly remarkable" after a record low 27 fatal crashes in January and 17 in February.
But they warned that April had been a deadly month in 2009 and last year, with 45 and 42 fatalities.